The US isn’t forcing anyone else to use USD. People around the world use USD because they are confident it will help them buy products and services they want in the future.
This. Fundamentally, the USD is the global reserve currency because the US is seen by the rest of the world as the most stable entity able to guarantee the future value of its currency: It's militarily powerful enough to guarantee its independence, and legally predictable as a "rule of law" nation and a stable democracy. If you want to park your assets anywhere, the safest bet is US treasuries. Everything else follows from that.
There is a common thread in the 1991 gulf conflict that Iraq was going to sell oil in alternative currencies.
The entire 1991 conflict is actually quite confusing, the majority western cold war apparatus moved to Saudi Arabia to fight the war. There aren't many reasons for why this was done.
Seems at least equally probable (IMO far more) that was due to the whole invading Kuwait thing.
Carter ten years prior: "Let our position be absolutely clear: An attempt by any outside force to gain control of the Persian Gulf region will be regarded as an assault on the vital interests of the United States of America, and such an assault will be repelled by any means necessary, including military force"
It appears that the US mislead¹ Saddam Husein into believing that the we would not intervene in the border dispute with Kuwait. This was enough assurance for him to go ahead with the decision to attack Kuwait. That action was then used by the US as a pretext for the invasion of Iraq.
It seems much more likely they were concerned about disruptions to energy which can immediately cripple an economy than some abstract vague mentions of using a different currency.
